Abstract : The report is a tutorial exposition of the AED-0 language and of a software engineering discipline based upon its use. The AED (Automated Engineering Design) System has been developed over a ten-year period by the M.I.T. Computer-Aided Design Project, culminating in release of the Version 3 AED-1 Compiler and associated system-building systems for use on IBM 360-series computers in both batch and time-sharing. Bootstraps to other computers are in progress. The AED-0 language, based on ALGOL-60, is the present language for the AED-1 Computer. The report describes a major subset of the AED-0 language and demonstrates its use. (Author)